The Mikey ProKit facilitates the removal of broken exhaust manifold bolts on GM LS: 4.8L, 5.3L, 5.7L, 6.0L, 6.2L V8 engines. It is the smallest and thinnest available to fit behind the firewall to make the repair. ProMAXX Toolâ??s exclusive screw-in bushings, which incorporate proprietary mating angles, once seated, has the most precise alignment with the cylinder head. 1999 - 2013 GM LS: 4.8L, 5.3L, 5.7L, 6.0L, and 6.2L V8 engines. Easily remove broken exhaust manifold bolts. Bottom Line: If you canâ??t get the most accurate hole placement, why use a tool at all? GM uses loctiteÂŽ when installing the studs at the factory, making them some of the most difficult to remove, especially up under the firewall. Therefore, we went one better. We incorporated two sets (125/188) of our tough Gold Tooling (Drill) Bits to first pilot, and then drill for the larger extractor to remove the loctiteÂŽ fitted broken bolt. Other kits use less effective, tapered left hand extractors only, which pinch the broken remnant in th, only amplifying the difficulty in removing the bolt and making the repair. ProMAXX kits incorporate non-deforming extractors that can be utilized both in the clockwise and counter-clockwise direction. This unlocks the broken remnant without pinching it in the cylinder head as in other kits which make your repair non productive. Other kits use inexpensive clamps or loose slip-fit bushings. Bolt Mikey in any position with our included precision fasteners to provide unparalleled, repeatable, and predictable results. Received a previous repair attempt or botched repair? No Problem. ProMAXX Tools larger plate holes provide the use of a thread repair kit that includes bushings, bits, and superior solid steel inserts, unlike spring-style, to completely restore the cylinder head to factory condition.